Re: [PATCH 1/2] hfsplus: prevent crash on exit from failed search

["Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>]

On Tue, Aug 21, 2018 at 04:02:24PM -0700, Andrew Morton wrote:
> On Mon, 02 Jul 2018 11:01:37 -0700 Viacheslav Dubeyko <slava@dubeyko.com> wrote:
> 
> > On Fri, 2018-06-29 at 15:34 -0300, Ernesto A. Fernández wrote:
> > > The hfs_find_exit() function expects fd->bnode to be NULL after a
> > > search has failed. The hfs_brec_insert() function may instead set
> > > it to an error-valued pointer. Fix this to prevent a crash.
> > > 
> > > Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
> > > Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
> > > ---
> > >  fs/hfsplus/brec.c | 7 ++++---
> > >  1 file changed, 4 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/fs/hfsplus/brec.c b/fs/hfsplus/brec.c
> > > index 808f4d8c859c..ed8eacb34452 100644
> > > --- a/fs/hfsplus/brec.c
> > > +++ b/fs/hfsplus/brec.c
> > > @@ -73,9 +73,10 @@ int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
> > >  	if (!fd->bnode) {
> > >  		if (!tree->root)
> > >  			hfs_btree_inc_height(tree);
> > > -		fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
> > > -		if (IS_ERR(fd->bnode))
> > > -			return PTR_ERR(fd->bnode);
> > 
> > 
> > Are you sure that no caller is used this error code? Did you check this?
> > 
> > Maybe, it makes sense to extract the error code and to show the error
> > message on the caller side instead of processing the simple NULL?
> > 
> 
> No response?  Could we please get this wrapped up?

I'm sorry, I thought you had picked this up already. Yes, I did check that
no caller was using this. fd->bnode is always assumed to be NULL on error.
Also, the error code is not lost, it's the return value of the function.